In the printing and copying industry, it has always been the responsibility of the production person to position the image on the work being printed or copied, so that the finished product has the best possible appearance. Traditionally, the procuction person is the pressman. In practice, he will set up a job on a press and run a first copy called a press sheet. Then he will take that press sheet to a table where measurements can be taken to determine whether or not adjustments must be made to the press prior to the production run.
Usually, he will utilize a light table, T-squares, rulers, and straight edges in an attempt to determine what corrections, if any, must be made in order to produce better copy. The light table is a large table having a glass top and an underlying light which shines through the glass and the paper to facilitate his work. Because of its size, the table generally serves more than one pressman, and is kept in a room apart from the pressroom.